Cognitive Pilot Channel (CPC) is a concept used in cognitive radio to provide information to cognitive mobiles about the available operators, Radio Access Technologies (RAT) and Frequencies available in a geographical area.
Two Major concepts for Cognitive Pilot Channel are proposed by the E3 project and ETSI RRS Group: Mesh based and Optimised broadcast approach.                In mesh based concept, a cell in a geographical area is divided into a plurality of meshes and information is provided about operators, RATs and Frequencies available in each mesh.        In optimised broadcast concept, information about all the RATs and frequencies available in the cells is transmitted at once.        
Although Mesh based concept is more precise than Optimised broadcast concept, it presents drawbacks resulting from the fact that the power used by the base station to broadcast said information is estimated to reach all mobiles. Thus no power control is used. The power is estimated at once to be sufficient for the users on the cell edge to be able to decode the broadcasted information.
Consequently, the same power is used for transmitting Cognitive Pilot Channel information to all meshes of the geographical area while the transmission of information to meshes close to the base station does not necessitate the same power as the transmission of said information to meshes situated on the outskirts of the geographical area. Thus a user equipment located in a peripheral mesh may not decode the information because of the power attenuation.
An object of the present invention is a method for optimizing the distribution of the transmission power in order to better control the power used to transmit the cognitive pilot channel (CPC) giving to a User Equipment the same probability of CPC content decoding in all the meshes.
Another object of the invention is a power control method that takes into account the attenuation du to the topography of each mesh in said geographical area.